So, I assume this is the pathway you're looking at. The top line is the typical track. The second line is the accelerated track. The third is for students needing extra support (and they say the hope is to phase out math 7/math 8). Clearly the design is to join the accelerated track in 4th grade but Math 5 to IM in sixth also happens (I know of examples at our MS, other posts have mentioned it). Once the HS credit courses begin with Algebra I, there's really no skipping levels (outside of magnet programs).